The Effect of Gene Editing by CRISPR-Cas9 of miR-21 and the Indirect Target MMP9 in Metastatic Prostate Cancer

Prostate cancer (PCa) has a high prevalence and represents an important health problem, with an increased risk of metastasis. With the advance of CRISPR-Cas9 genome editing, new possibilities have been created for investigating PCa. The technique is effective in knockout oncogenes, reducing tumor resistance. MMP9 and miR-21 target genes are associated with PCa progression; therefore, we evaluated the MMP-9 and miR-21 targets in PCa using the CRISPR-Cas9 system. Single guide RNAs (sgRNAs) of MMP9 and miR-21 sequences were inserted into a PX-330 plasmid, and transfected in DU145 and PC-3 PCa cell lines. MMP9 and RECK expression was assessed by qPCR, WB, and IF. The miR-21 targets, integrins, BAX and mTOR, were evaluated by qPCR. Flow cytometry was performed with Annexin5, 7-AAD and Ki67 markers. Invasion assays were performed with Matrigel. The miR-21 CRISPR-Cas9-edited cells upregulated RECK, MARCKS, BTG2, and PDCD4. CDH1, ITGB3 and ITGB1 were increased in MMP9 and miR-21 CRISPR-Cas9-edited cells. Increased BAX and decreased mTOR were observed in MMP9 and miR-21 CRISPR-Cas9-edited cells. Reduced cell proliferation, increased apoptosis and low invasion in MMP9 and miR-21 edited cells was observed, compared to Scramble. CRISPR-Cas9-edited cells of miR-21 and MMP9 attenuate cell proliferation, invasion and stimulate apoptosis, impeding PCa evolution.

Overexpression of miR-17-5p may negatively impact p300/CBP factor-associated inflammation in a hypercholesterolemic advanced prostate cancer model

BACKGROUND

Previously, we demonstrated that cholesterol triggers the increase in p300/CBP-associated factor (PCAF), targeted by miR-17-5p. The p300, IL-6, PCAF, and miR-17-5p genes have important and contradictory roles in inflammation and prostate cancer (PCa). This study aimed to demonstrate the potential anti-inflammatory effect of miR-17-5 in an advanced PCa model with diet-induced hypercholesterolemia.

METHODS AND RESULTS

In vitro, using the PC-3 cell line, we show that induction of miR-17-5p reduces p300 and PCAF expression, increases apoptosis, and decreases cell migration. Furthermore, we demonstrate that supplementing this same cell with cholesterol (2 µg/mL) triggers increased p300, IL-6, and PCAF. In vivo, after establishing the hypercholesterolemic (HCOL) model, xenografts were treated with miR-17-5p. Increased expression of this miR after intratumoral injections attenuated tumor growth in the control and HCOL animals and reduced cell proliferation.

CONCLUSION

Our results demonstrate that inducing miR-17-5p expression suppresses tumor growth and inflammatory mediator expression. Further studies should be conducted to fully explore the role of miR-17-5p and the involvement of inflammatory mediators p300, PCAF, and IL-6.

Intratumoral Restoration of miR-137 Plus Cholesterol Favors Homeostasis of the miR-137/Coactivator p160/AR Axis and Negatively Modulates Tumor Progression in Advanced Prostate Cancer

MicroRNAs (miRNAs) have gained a prominent role as biomarkers in prostate cancer (PCa). Our study aimed to evaluate the potential suppressive effect of miR-137 in a model of advanced PCa with and without diet-induced hypercholesterolemia. In vitro, PC-3 cells were treated with 50 pmol of mimic miR-137 for 24 h, and gene and protein expression levels of SRC-1, SRC-2, SRC-3, and AR were evaluated by qPCR and immunofluorescence. We also assessed migration rate, invasion, colony-forming ability, and flow cytometry assays (apoptosis and cell cycle) after 24 h of miRNA treatment. For in vivo experiments, 16 male NOD/SCID mice were used to evaluate the effect of restoring miR-137 expression together with cholesterol. The animals were fed a standard (SD) or hypercholesterolemic (HCOL) diet for 21 days. After this, we xenografted PC-3 LUC-MC6 cells into their subcutaneous tissue. Tumor volume and bioluminescence intensity were measured weekly. After the tumors reached 50 mm3, we started intratumor treatments with a miR-137 mimic, at a dose of 6 μg weekly for four weeks. Ultimately, the animals were killed, and the xenografts were resected and analyzed for gene and protein expression. The animals' serum was collected to evaluate the lipid profile. The in vitro results showed that miR-137 could inhibit the transcription and translation of the p160 family, SRC-1, SRC-2, and SRC-3, and indirectly reduce the expression of AR. After these analyses, it was determined that increased miR-137 inhibits cell migration and invasion and impacts reduced proliferation and increased apoptosis rates. The in vivo results demonstrated that tumor growth was arrested after the intratumoral restoration of miR-137, and proliferation levels were reduced in the SD and HCOL groups. Interestingly, the tumor growth retention response was more significant in the HCOL group. We conclude that miR-137 is a potential therapeutic miRNA that, in association with androgen precursors, can restore and reinstate the AR-mediated axis of transcription and transactivation of androgenic pathway homeostasis. Further studies involving the miR-137/coregulator/AR/cholesterol axis should be conducted to evaluate this miR in a clinical context.

Can increased expression of miR-Let-7c reduce the transition potential of high-grade urothelial carcinoma?

BACKGROUND

Bladder cancer is the leading transitional cell carcinoma affecting men and women with high morbidity and mortality rates, justifying the need to develop new molecular target therapies using microRNAs. This study aimed to evaluate the behavior of the T24 cell line after transfection with miR-Let-7c precursor mimic through invasion, migration, apoptosis, and cell cycle assays. METHODS AND RESULTS: T24 cell was transfected with the Let-7c mimic and its respective control and evaluated after 24 h. The expression levels of miR-Let-7c were analyzed by qPCR. We performed wound healing, Matrigel and flow cytometry, apoptosis, and cell cycle assays to determine its effect on cellular processes. Cells transfected with miR-Let-7c showed increased apoptosis rates (p = 0.019), decreased migration 24 h (p = 0.031) and 48 h (p = 0.0006), invasion potential (p = 0.0007), and cell proliferation (p = 0.002).

CONCLUSIONS

Our results demonstrate that miR-Let-7c can act in different pathways of the carcinogenic cellular processes of muscle-invasive urothelial carcinoma cells, inhibiting cell proliferation and increasing apoptosis levels, consequently limiting their invasion potential. However, further studies should be carried out better to elucidate this microRNA's role in high-grade urothelial carcinomas and unveil which targets this microRNA may present, which are intrinsically related to the cancer survival pathways.

Abstract 5399: Correlation of a microRNA expression profile and the prognosis of penile cancer: A prospective study using microarray data analysis

Introduction and objective: Penile cancer is a rare disease that has high morbidity and mortality rates. While a few biomarkers related to prognosis have been previously described to date none of them was adopted in clinical practice. Our aim was to identify a molecular signature based on miRNA expression levels that could identify those patients with high risk of metastatic penile carcinoma.

Methods: We prospectively collected fresh samples of primary tumors from 11 patients with squamous cell penile carcinoma who underwent surgical treatment between July/2015 and June/2017. Five patients had localized disease (non-metastatic group) and 6 had inguinal lymph node metastases (metastatic group). RNA was purified and microarray analysis was performed using miRNA 4.0 Genechip (Affymetrix). We identified differentially expressed miRNAs (DEmiRs) comparing metastatic in relation to non-metastatic groups using TAC Software (Affymetrix), fold change (FC) > 1.5 and p<0.05. Their validated/predicted targets were investigated using miRTarBase 7.0, mirWalk 2.0 and/or MetaCore 6.32 softwares. Enrichment Pathways analysis was performed using Enrichr. Up/downstream interaction networks were identified by MetaCore v6.32 software.

Results: Twenty two DEmiRs (17 up- and 5 downregulated) were identified when comparing metastatic in relation to non-metastatic patients. Hierarchical clustering analysis showed a set of 7 DEmiRs (miR-181c-5p, 744-5p, 196b-5p, 200a-5p, 152-3p, 421, 149-5p) which clustered samples according to prognosis. Network interaction analyses identified transcriptional factors (NANOG, Oct-3/4, SOX2 and c-Jun) that commonly regulate those DEmiRs. Moreover, TGFB, CMYC, RICTOR, ADAM-17 and PTEN are some of the common targets of those DEmiRs and are more likely to be deregulated. Validated and predicted targets of these 7 DEmiRs were found enriched in relevant pathways such as “Proteoglycans in cancer”, “Pathways in cancer”, “miRNAs in cancer” and “Signaling pathways regulating pluripotency of stem cells”. Among their targets, CMYC, SP1, ESR1 and AR are examples of hubs which presented the highest number of network interactions.

Conclusions: We found 7 DEmiRs correlated with prognosis and capable of discriminating metastatic from non-metastatic tumors. In addition, their targets are enriched in cancer-related pathways and could be potential biomarkers for prognosis in penile cancer.

Citation Format: Tatiane K. Furuya, Claudio B. Murta, José Pontes Jr, Miyuki Uno, Alexis Carrasco, Laura C. Sichero, Luisa L. Villa, Rafael F. Coelho, Giuliano B. Guglielmetti, Mauricio D. Cordeiro, Kátia R. Leite, Miguel Srougi, Roger Chammas, William C. Nahas. Correlation of a microRNA expression profile and the prognosis of penile cancer: A prospective study using microarray data analysis [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 5399.

Postconditioning ameliorates lipid peroxidation in liver ischemia-reperfusion injury in rats

PURPOSE

Liver ischemia-reperfusion injury is a phenomenon presents in events like liver resections and transplantation. The restoration of blood flow may leads to local and systemic injury. Several techniques have been developed in order to avoid or ameliorate ischemia-reperfusion injury in clinical situations. The application of a stutter reperfusion after the ischemic event (postconditioning) could alters the hydrodynamics and stimulates endogenous mechanisms that attenuate the reperfusion injury. The present study was designed to evaluate the potential protective effect of postconditioning in a model of ischemia-reperfusion in rats.

METHODS

Hepatic anterior pedicle of median and left anterolateral segments were exposed and clamped for 1 hour. Two hours later, clamp was released in two different ways: Control Group (n=7): clamp was release straightforward; Postconditioning Group (n=7): clamp was released intermittently. Lipid peroxidation (malondialdehyde) and expression of the glutathione-s-transferase-alpha-3 gene were studied.

RESULTS

Lipid peroxidation was significantly decreased in ischemic and non-ischemic liver by postconditioning. GST- alpha3 gene was overexpressed in post-conditioned group, but not significantly.

CONCLUSION

Postconditioning induced hepatoprotection by reducing lipid peroxidation in the ischemic and non-ischemic liver.

Analysis of the clinicopathological characteristics of patients with upper urinary tract transitional cell carcinoma

OBJECTIVE

To describe the clinicopathological characteristics of patients with upper urinary tract transitional cell carcinomas who are treated surgically and to analyze the occurrence of bladder tumors as well as the development of metastases outside the urinary tract.

MATERIALS AND METHODS

The study comprised a retrospective analysis of 25 patients treated between February 1994 and August 2006. The variables analyzed were: patient age, gender, and clinical presentation; diagnostic methods; pathologic characteristics at the primary site of the tumor (pelvis or ureter); tumor stage and grade; and presence of carcinoma in situ, microvascular invasion and squamous differentiation. The Kaplan-Meier method and the Log-Rank test were used for statistical analysis of bladder recurrence-free survival.

RESULTS

Eighty-four percent of patients were male, and macroscopic hematuria was the most common clinical presentation. The majority of cases (56%) were infiltrative (T2-T3) and high-grade (76%) tumors. Synchronous or metachronous bladder tumors were found in 72% of cases. Five (20%) patients had a history of bladder tumor before the diagnosis of upper urinary tract transitional cell carcinomas. The mean follow-up period was 36 months (range: 1.5 to 156). During the follow-up period, eleven (44%) patients developed bladder tumors. After five years, the probability of being free of bladder tumor recurrence was 40%. No pathological variable was predictive for bladder tumor recurrence. Four patients presented disease recurrence outside the urinary tract.

CONCLUSIONS

The presence of metachronous bladder tumors is more often observed after the diagnosis of upper urinary tract transitional cell carcinomas. All of these patients should undergo rigorous follow-up during the postoperative period. Only patients with infiltrative and high-grade tumors developed metastases outside the urinary tract.

Acinar cell carcinoma of the pancreas: is the absence of neuroendocrine component related to a more malignant behavior?

BACKGROUND/AIMS

Acinar cell carcinomas are uncommon malignant tumors of the pancreas, accounting for 1-2% of all the cases of exocrine pancreatic tumor. Some authors have estimated acinar cell tumors to be as aggressive as ductal adenocarcinoma of the pancreas whereas other series showed acinar cell tumors to have a favorable clinical outcome. This discrepancy in prognosis may be related to the cellular components of the tumor.

METHODOLOGY

With the aim to evaluate the possible relationship between the presence of neuroendocrine differentiation and behavior of these tumors, the authors reviewed all patients presenting acinar cell carcinoma of the pancreas in the last 5 years with emphasis in the immunohistochemical evaluation.

RESULTS

Four patients presented neuroendocrine differentiation on immunohistochemical evaluation and had a more benign outcome. Two patients without neuroendocrine component had a disseminated disease at presentation. This data suggests that this tumor is less aggressive than ductal adenocarcinoma and even with nodal involvement, long-term survival after complete resection can be achieved.

CONCLUSIONS

It is possible that the absence of neuroendocrine component may be related to a less favorable outcome and adjuvant therapy may be necessary. Due to the rarity of this pancreatic tumor, this relationship remains to be confirmed with a multicentric study including a larger number of patients.

Microvascular tumour invasion in renal cell carcinoma: the most important prognostic factor

OBJECTIVE

To evaluate the role of microvascular invasion (MVI) in the primary lesion for predicting tumour behaviour in patients with renal cell carcinoma (RCC), as reliable clinical prognostic factors would be very valuable.

PATIENTS AND METHODS

MVI was assessed in 230 patients with clinically localized RCC (stages T1-4NxM0) who had a radical nephrectomy and/or nephron-sparing surgery. The median (range) follow-up was 48 (3-130) months. The impact of MVI on disease progression and its correlation with clinical and histopathological factors was analysed, including whether patients were symptomatic or not at presentation, Fuhrman nuclear grade, tumour size, pathological stage and lymph node metastasis. Regression analyses and survival curves were used to determine if MVI was associated with the prognosis of RCC.

RESULTS

There was MVI in 59 patients (26%); of these, 46% developed disease recurrence. Among the 171 patients with no MVI, only 11 (6%) had tumour recurrence. MVI was associated with tumour diameter, nuclear grade, pathological stage, lymph node metastasis and the presence of sarcomatous elements in the tumour. Multivariate analysis showed that MVI was an independent predictor of disease recurrence and the most important factor related to death.

CONCLUSION

MVI is an independent predictor of prognosis in patients with RCC.

Impact of Clinicopathological Parameters in Patients Treated for Renal Cell Carcinoma

PURPOSE

We determined the impact of clinical and pathological factors in the outcome of patients with renal cell carcinoma treated surgically.

MATERIALS AND METHODS

We retrospectively reviewed the records of 230 consecutive patients after radical or partial nephrectomy. We analyzed clinical (incidental or symptomatic disease) and pathological (tumor size, histological type, Fuhrman nuclear grade, microvascular invasion and lymph node involvement) parameters. Disease-free and cancer specific survival curves were individualized for each parameter and on multivariate analysis.

RESULTS

Median postoperative followup was 34.3 months, median time to recurrence was 22 months and mean overall survival was 130 months. A total of 40 patients (17.3%) presented with local and/or metastatic recurrence and 32 (13.9%) died of the disease. Five-year disease-free and cancer specific survival rates on univariate analysis were 56.7% and 64% for symptomatic tumors, 76.6% and 68% for clear cell carcinoma, 26.9% and 39% for sarcomatoid tumors, 34.7% and 47.5% for high grade tumors, 26.7% and 39.7% for microvascular invasion, 37.5% and 49.1% for tumors larger than 7 cm, and 11% and 32% for lymph node involvement, respectively. On univariate analysis patients with lymph node involvement and microvascular invasion had a poor prognosis. Multivariate analysis showed that the single independent prognostic factor was microvascular invasion.

CONCLUSIONS

This study points out different clinical and pathological prognostic factors of survival in patients treated for renal cell carcinoma. Microvascular invasion was the only independent prognostic factor on multivariate analysis.

Overexpression of HER2/neu oncoprotein in cytologic specimens

OBJECTIVE

To assess the rate of HER2/neu overexpression in cytologic specimens by immunocytochemistry (ICC) and compare these results in matched surgical specimens by immunohistochemistry (IHC) and fluorescence in situ hybridization (FISH), when available.

STUDY DESIGN

All cytologic specimens processed for HER2/neu evaluation by ICC (72 cases) and available corresponding histologic specimens (16 cases) were retrieved from our files. ICC was applied to previously Papanicolaou stained, routine fine needle aspirations specimens (64 cases) and cytocentrifuged, alcohol-fixed, fluid specimens (8 cases). FISH was performed on 6 histologic specimens.

RESULTS

Overexpression of HER2/neu was seen in 7/22 breast cancers (31.8%), 3/18 pulmonary adenocarcinomas (16.6%), 2/5 colorectal adenocarcinomas (40%), 1/2 adenocarcinomas of the biliary system (50%), 1/3 thyroid papillary carcinomas (33.3%) and 1/3 prostate adenocarcinomas (33.3%). Sixteen cases had IHC in matched histologic specimens: 14 (87.5%) cases were concordant (11 negative and 3 positive in both specimens), 1 case was negative in the cytologic specimen and positive in the histologic specimen (with no amplification by FISH), and 1 case was positive in the cytologic specimen and negative in the histologic specimen (not informative by FISH).

CONCLUSION

Our data suggest that overexpression of HER2/neu oncoprotein can be successfully detected in routine cytologic specimens, providing a simple, fast and cost-effective method of selecting patients for specific treatment.

Effect of platelet-activating factor antagonists (BN-52021, WEB-2170, and BB-882) on bacterial translocation in acute pancreatitis

Bacterial translocation is an important source of pancreas infection in acute pancreatitis. The effect of platelet-activating factor (PAF) in the pathogenesis of acute pancreatitis has been proved in various studies. The aim of this study was to determine whether potent PAF antagonists influence bacterial translocation in acute pancreatitis. Acute pancreatitis was induced in 62 Wistar rats by injection of 2.5% sodium taurocholate into the biliopancreatic duct. The rats treated with PAF factor antagonists received intravenous injection of WEB-2170 (10 mg/kg), lexipafant (5 mg/kg), and BN-52021 (5 mg/kg) 30 minutes before induction of acute pancreatitis. Six hours after induction of acute pancreatitis, bacteriologic cultures and histologic scoring of tissues were performed. There was a statistically significant reduction in bacterial translocation to the mesenteric lymph nodes and liver but not to the pancreas of the rats treated with PAF antagonists. No significant increase in the intestinal bacterial population of any group was found. There were no statistical differences between the pancreatic histologic scores of the groups. PAF antagonists reduced bacterial translocation to distant sites other than the pancreas, preventing the bacterial dissemination that occurs in the early phase of acute pancreatitis and may have beneficial effects on the evolution of this disease.

Abnormal Expression of MDM2 in Prostate Carcinoma

Mutation of p53 is rare in localized prostate carcinoma. The oncoprotein MDM2, whose gene has a response element for p53, promotes the degradation of p53 protein and inhibits its transcriptional activation of genes related to cell cycle arrest and apoptosis, constituting a negative feedback control. We studied p53 and MDM2 expression by immunohistochemistry and looked for mutations in p53 exons 5 to 8 by polymerase chain reaction-single strand conformational polymorphism in 118 patients submitted to radical prostatectomy for localized prostate cancer. In 28 cases, we studied cell proliferation by immunohistochemistry, using antibody for Ki-67, and apoptosis by the deoxynucleotidyl transferase mediated dUTP biotin nick end labeling technique. Although no p53 mutations were found, p53 protein was detected in 31.4% of the cases, and these cases had higher Gleason scores (P = .03) and more advanced tumor stages (P = .02). MDM2 was overexpressed in 40.7% of the cases, and these cases had greater tumor volumes (P = .001). Tumors that were positive for both p53 and MDM2 were larger (P = .003) and of more advanced stage (P = .03). Within the 28-case subset, the proliferative index was higher among MDM2-positive tumors (P = .046), and the apoptotic index was lower among p53-positive tumors (P = .01). We conclude that, although p53 mutation is a rare event in prostate carcinogenesis, the detection of p53 protein by immunohistochemistry is common and is associated with decreased apoptosis and increased histologic grade and tumor stage. We also conclude that the overexpression of MDM2 has a role in prostate carcinogenesis, being frequently detected and associated with increased cell proliferation and tumor volume. Finally, we propose that the MDM2-positive/p53-positive phenotype identifies prostate cancers with aggressive behavior.

Urinary continence and pathological outcome after bladder neck preservation during radical retropubic prostatectomy: a randomized prospective trial

PURPOSE

Bladder neck preservation during radical prostatectomy has been advocated for improving urinary continence. We compared bladder neck preservation and resection in a randomized trial, looking at continence rates and surgical cancer control.

MATERIALS AND METHODS

Patients with stage T1c-T2c prostate cancer underwent radical retropubic prostatectomy with maximal preservation of the external urinary sphincter. Bladder neck preservation or resection was chosen by chance during surgery. Urinary continence (1 or no protective pad daily) was assessed by interview 2 days after catheter removal, and 2 and 6 months after surgery. The surgeon, pathologist and interviewer were the same throughout. Neither patient nor interviewer knew which procedure was done. Planned enrollment was 120.

RESULTS

Enrollment was stopped after 70 patients because surgical margins were positive only at the bladder neck in 10% of the preservation group but in none of the resection group (p = 0.08). Each group was assigned 35 patients but the bladder neck could not be preserved in 4 and 1 died, leaving 31 in the preservation group and 38 in the resection group. There were no statistically significant differences between groups in early or late urinary continence rates. Two days after catheter removal, and 2 and 6 months after surgery the respective rates were 79%, 87% and 95% with resection, and 67%, 87% and 97% with preservation.

CONCLUSIONS

In our opinion bladder neck preservation during radical retropubic prostatectomy does not improve urinary continence and might compromise cancer control. The external sphincter appears more important for continence after radical prostatectomy.

Monoclonality of asynchronous bilateral lymphoma of the testis

OBJECTIVES

Lymphoma is the most frequent testicular malignancy in men over 60 years of age. Even though patients present initially with localized disease, the high incidence of bilateral involvement, synchronous or not, and early systemic dissemination are characteristic of these neoplasms. Sometimes the interval between tumor involvement of both testes is long. The question is raised whether either the patient has a predisposition to present new clones of transformed lymphocytes, or the same disease using the same pathway from a systemic reservoir infiltrates the contralateral testis.

METHOD

Polymerase chain reaction and DNA sequencing were used to detect immunoglobulin heavy chain (IgH) rearrangement in paraffin-embedded specimens from asynchronous tumors affecting the right and left testis of a 85-year-old man with an interval period of 13 months.

RESULTS

Both tumors showed the same IgH rearrangement.

CONCLUSIONS

The lymphoma affecting the left and right testis derived from the same clone. It makes a strong case that lymphoma of the testis is the first manifestation of a systemic disease and should be treated aggressively early at the beginning of the disease.

Immunohistochemical Mdm2 expression in minor salivary gland tumours and its relationship to p53 gene status

Mdm2 protein is a cellular regulator of p53 protein activity. Minor salivary gland tumours were investigated for immunohistochemical expression of Mdm2 protein and for p53 gene status. Formalin-fixed sections were submitted to monoclonal antibody anti-Mdm2 through use of the streptavidin-biotin method. Nuclear immunoreactivity was scored 1 (0-25% nuclei positive), 2 (26-50%), 3 (51-75%) and 4 (> 75%). The scores found were: PLGA = 1-4; ACC = 3 and 4; ACA = 2 and 4; PA = 3. Genomic DNA of p53 gene exons 5-8 was examined by polymerase chain reaction and no alterations were detected. The strong immunohistochemical Mdm2 expression may represent an alternative mechanism to the development of salivary gland tumours.

Analysis of p53 expression and proliferative assessment using PCNA in localized prostate carcinoma

The surgical specimens from 51 men submitted to radical prostatectomy for localized prostate cancer were examined by immunohistochemistry using proliferation cell nuclear antigen (PCNA) monoclonal antibody to evaluate the proliferative index (PI). The relationship between PI, biological variables and p53 protein expression was evaluated by immunohistochemistry. PI was low in invasive localized prostate carcinoma (mean, 12.4%) and the incidence of PCNA-positive cells was significantly higher in tumors with p53 expression (P = 0.0226). There was no statistical difference in PCNA values when biological parameters such as Gleason score, tumor volume, extraprostatic involvement, seminal vesicle infiltration or lymph node metastasis were considered. We conclude that proliferative activity is usually low in prostate carcinoma but is correlated with p53 immune staining, indicating that p53 is important in cell cycle control in this neoplasm.

Detection of codon 12 mutation in the K-ras oncogene in pancreatic tumors

Mutations at codons 12, 13, or 61 of the H-ras, K-ras, and N-ras have been detected in human neoplasias by a variety of techniques. Some of these techniques are very sensitive and can detect K-ras mutation in 90% of the cases of pancreatic adenocarcinomas. We analyzed 11 samples of pancreatic adenocarcinoma, three samples of pancreatic mucinous cystadenoma, and two samples without tumors in formalin-fixed paraffin embedded tissue sections. K-ras mutations at codon 12 were detected by a two-step PCR-enriched technique in all the samples of pancreatic adenocarcinoma, but not in cystadenoma or control samples. This technique may be useful for early detection of pancreatic cancer.

[Antioxidative effect of N2-mercaptopropionylglycine (N2 MPG) in experimental acute pancreatitis]

The N2-Mercaptopropionylglycine (N2-MPG) is a potent antioxidant by inhibiting the abnormal production of xantina-oxidase. The aim of this research is to analyze the antioxidant capacity of this tiol compound by offering some protection to pancreatic tissue in the acute pancreatitis (AP). The induction of AP was obtained through two methods: a) supramaximal dose of cerulein; b) infusion of 2.5% sodium taurocholate into the biliopancreatic duct of the rat. Thirty-six male Wistar rats (220-270 g) were divided into four groups. AP with cerulein (Two parenteral doses of 20 micrograms/kg; one hour interval): in two groups: GI: nineteen rats previously treated with N2-MPG (100 mg/kg) ten minutes before AP. GII (control): seventeen animals which received saline 0.9%. AP with taurocholate (0.5 ml into the main biliopancreatic duct): in other two groups: GIII: eleven rats previously treated with N2-MPG (100 mg/kg) ten minutes before AP. GIV (control): fifteen animals which received saline 0.9%. The albumin leakage into the cell interstice as an inflammatory parameter was measured through Evans-Blue (EB) colorimetry, that links totally with serum albumin after injection into the pancreatic tissue, immediately before induction of AP. The rats were sacrificed one hour after. Water tissue content was also measured. There was a relevant reduction of EB leakage in GI (344 +/- 27 micrograms/gtissue) when compared to GII (729 +/- 84 micrograms/gtissue), p < 0.01, and in GIII (386 +/- 52 micrograms/gtissue) when compared to GIV (543 +/- 53 micrograms/gtissue), p < 0.05. There was no difference in tissue water content between GI (88.2 +/- 0.6%) and GII (87.4 +/- 0.9%), but certainly between GIII (77.7 +/- 2.1%) and GIV (82.8 +/- 1.2%), p < 0.05. The amilase levels didn't show any difference among the four groups. These results suggest that the use of the antioxidant N2-MPG offers a protective action, at least in rats, reducing the severity of AP induced by supramaximal dose of cerulein, and even in a more severe AP such as produced by sodium taurocholate at 2.5%, although apparently not interfering with its pathogenesis. It also strengthens the actual participation of free radicals of oxygen in the physiopathology of acute pancreatitis.

[Hepatic lesion in experimental acute pancreatitis. Influence of pancreatic enzyme storage reduction]

Acute Pancreatitis (AP) is known to produce morphologic and functional changes in liver. Administration of low doses of caerulein significant decreases the content of pancreatic enzymes, leading to reduced mortality of animals submitted to AP. The present study was designed to assess the effect of acute reduction of pancreatic enzymatic content in the hepatic mitochondrial function. Wistar male rats, submitted to AP by injection of Na thaurocholate into the pancreatic duct, with and without previous i.v. injection of 0.133 microgram Kg-1h-1 of caerulein for three hours, were divided in four groups: Group I: No caerulein infusion and AP; Group II: Previous caerulein infusion and with AP; Group III: Caerulein infusion without AP; Group IV (control): No caerulein infusion and without AP. After 2 hours of induction of AP the livers were removed and prepared to the mitochondrial oxidative and phosphorylative activities, measured polarographically with determination of oxygen consumption without ADP (Basal respiration-State 4) and in the presence of ADP (Activated respiration-State 3). Ascitic fluid contents of amylase, trypsin and total protein were routinely determined. After 2 hours of AP there was a significant increase in state 4 respiration (41%) and a decrease in respiratory control ratio and in ADP/O ratio (p < 0.05) in animals of Group I (AP without caerulein) when compared to Group II (AP with caerulein) (Table 1). Ascitic fluids contents of amylase (A) and trypsin (T) showed decrease in animals of Group II with AP that received previous caerulein infusion (A = 80 +/- 10 U/ml, T = 9.75 +/- 1.25 U/ml), when compared to animals of Group I that did not receive caerulein (A = 231 +/- 24, T = 40.32 +/- 5.19) (p < 0.001). Caerulein infusion by itself (Group III) did not have any influence on mitochondrial liver dysfunction. Reduction of pancreatic enzyme content through caerulein infusion attenuates the damage of mitochondrial respiration, demonstrated by uncoupling phase on mitochondrial function in experimental AP. Further studies are needed to elucidate this phenomena, but it is probably related to the decreased of the pathogenic effects of pancreatic activated enzymes that reach the systemic circulation in reduced amounts.

Hepatic damage during acute pancreatitis in the rat

We studied the alterations in the metabolism of liver mitochondria in rats with acute pancreatitis. Male Wistar rats were allocated to a control group (group I) and to five other groups corresponding to 2, 4, 12, 24 and 48 h after the induction of acute pancreatitis by the injection of 5% sodium taurocholate into the pancreatic duct. Sham-operated animals were submitted to the same surgical steps except for the induction of acute pancreatitis. Mitochondrial oxidation and phosphorylation were measured polarographically by determining oxygen consumption without ADP (basal respiration, state 4) and in the presence of ADP (activated respiration, state 3). Serum amylase, transaminases (ALT and AST) and protein were also determined. Ascitic fluid, contents of amylase, trypsin and total protein were also determined and arterial blood pressure was measured in all groups. In ascitic fluid, trypsin and amylase increased reaching a maximum at 2 and 4 h, respectively. Serum amylase increased at 2 h reaching a maximum at 4 h. Serum transaminase levels increased at 12 and 24 h. After 2 h (and also 4 h) there was an increase in state 4 respiration (45.65 +/- 1.79 vs 28.96 +/- 1.50) and a decrease in respiration control rate (3.53 +/- 0.09 vs 4.45 +/- 0.08) and in the ADP/O ratio (1.77 +/- 0.02 vs 1.91 +/- 0.01) compared to controls (P < 0.05). These results indicate a disruption of mitochondrial function, which recovered after 12 h. In the 48-h groups there was mitochondrial damage similar to that occurring in ischemic lesion. Beat-to-beat analysis (30 min) showed that arterial blood pressure remained normal up to 24 h (111 +/- 3 mmHg) while a significant decrease occurred in the 48-h group (91 +/- 4 mmHg). These data suggest biphasic damage in mitochondrial function in acute pancreatitis: an initial uncoupled phase, possibly secondary to enzyme activity, followed by a temporary recovery and then a late and final dysfunction, associated with arterial hypotension, possibly related to ischemic damage.

[Physiopathology of lung injury in acute pancreatitis]

Clinically detectable signs of lung injury develop in up to 50-70 percent of patients with acute pancreatitis. Despite that, the physiopathology of the lung injury associated with acute pancreatitis is unclear so far. Pulmonary edema is the main respiratory complication in acute pancreatitis. Increased permeabilities of the pulmonary endothelial and alveolar epithelial barriers are the causes of the pulmonary edema. Several factors have been regarded as the cause to pulmonary edema: release of pancreatic-derived proteolytic enzymes, oxygen-free radicals, phospholipase A2, free fat acids, tumor necrosis factor, platelet activating factor, arachidonic acid metabolites and pulmonary embolization. Understanding lung injury physiopathology enables physicians to a better therapeutic approach of the patients with acute pancreatitis. The aim of this paper is to expose the theories that explain the pancreatic-derived lung injury.

[Lung injury in acute pancreatitis. Influence of pancreatic enzymes reduction]

A previous report has show that cerulein in physiological doses reduces the rate mortality of pancreatitis by decreasing the enzyme content of the pancreas. Clinically detectable signs of lung injury develop in up to 50-70 percent of patients with acute pancreatitis. The aim of the present study was to assess the effect of acute reduction of pancreatic enzyme content on the pancreatitis pulmonary injury. Experimental haemorrhagic pancreatitis was induced by intraductal injection of 5 per cent sodium taurocholate in two groups of Wistar rats: group I (pancreatitis) and group II (pancreatitis after decreasing pancreatic enzyme content). Dye Evans blue was used to evaluate the lung injury. The degree of histologically observed lesions were similar in both groups, but the pulmonary lesion was smaller in group II than group I (p < 0.05).

IN CONCLUSION

1) pancreatitis' pulmonary lesion may be related with pancreatic enzymes that reach the blood stream and 2) the reduction of the pancreatic enzyme content has a beneficial effect on acute pancreatitis and reduces its pulmonary injury.

[Simplified model of induction of experimental acute pancreatitis with a supra-maximal dose of cerulein]

The study was performed to compare an usual method of induction of acute experimental pancreatitis with a simplified, easier and faster induction through a subcutaneous and intravenous injection of cerulein, with good reproducibility as compared to the literature. Four groups were studied. In the group I, continuous three hour intravenous injection of 15 micrograms/Kg of cerulein, was given. Group II was a control group with saline infusion. Group III received a subcutaneous injection of 20 micrograms/Kg and an intravenous injection of 20 micrograms/Kg of cerulein one hour later. Group IV was the control group with saline. The results of biochemical measurements, such as tecidual trypsinogen, chimotrypsinogen, proelastase, cathepsin and serum amylase, showed no difference between the two methods. Histologic study revealed edematous pancreatitis in group I and III, with moderate acinar necrose in group III. These results suggest that the proposed simplified method induces enough acute and edematous pancreatitis to allow studies in physiopathology and therapeutics.

[Focal nodular hyperplasia of the liver observed in a patient undergoing prolonged therapy with ketoconazole]

The authors report on a 44 year old man presenting focal nodular hyperplasia of the liver associated with prolonged ketoconazole therapy in the absence of known intake of either estrogens of androgens as well as of any factor that could cause hyperproduction of estrogens. It seems possible the existence of an etiopathogenic relationship between prolonged ketoconazole therapy and focal nodular hyperplasia of the liver since ketoconazole inhibits steroidogenesis and can also increase the estradiol-testosterone ratio (E/T). This hormonal alteration is known to play an important role in the pathogenesis of several hepatic neoplasms, including focal nodular hyperplasia.